The present invention is concerned generally with an optical system and method for generating an image on a projection screen using a highly compact geometry. More particularly, the optical system uses polarized light manipulated by at least one of a conicoid, or plane optical elements to effect a folded mirror system to project an image onto a screen.
Currently available image projection systems are quite large with their dimensions (particularly the cabinet depth) making such systems cumbersome and requiring special preparation of a space for their use. Furthermore, in such projection systems which employ LCDs the light output from the source has all polarized states but the system makes use of only one state of polarization, thus eliminating about half the light available for imaging on the projection screen.
It is, therefore, an object of the system to provide an improved image projection system and method of use.
It is another object of the system to provide a novel system and method for projecting an image on a screen using a highly compact optical system.
It is a further object of the invention to provide an improved system and method for processing polarized input light using plane reflecting and transmitting optical elements.
It is a further object of the invention to provide an improved system and method for processing polarized input light using conicoidal optical elements.
It is yet another object of the invention to provide an improved system and method for manipulating polarized light using a primary paraboloidal (or modified paraboloidal) element which is coaxially aligned with an inner, smaller secondary hyperboloidal (or modified hyperboloidal) element or ellipsoidal (or modified ellipsoidal) element to output a single polarization state image for display on a projection screen.
It is yet a further object of the invention to provide an improved system and method for manipulating polarized light using a convex conicoidal reflecting surface, a negative lens, a polarization-selective and converting reflecting/transmitting plane and a Fresnel lens, so as to output a single polarization state image for display on a projection screen.
It is also an object of the invention to provide an improved system and method for manipulating polarized light using a convex conicoidal reflecting surface, a polarization converting plane, a polarization-selective mirror plane, a positive lens section and a Fresnel lens, to output a single polarization state image for display on a projection screen.
It is yet another object of the invention to provide an improved system and method for manipulating polarized light using a primary concave conicoidal reflector which is coaxially aligned with an inner, smaller secondary convex conicoid reflector that converts polarization state and that selectively reflects/transmits depending on polarization state to output a single polarization state image for display on a projection screen.
It is an additional object of the invention to provide a novel system and method for supplying light components of substantially orthogonal polarizations for separate areas of an image for output onto a projection screen.
It is still another object of the invention to provide an improved system and method for separating different light polarization states to reconstruct an image on a projection screen.
It is also an additional object of the invention to provide a novel system and method for providing light of a first polarization to a first LCD region and light of another polarization to a second LCD region for controlled transmission of images onto a projection screen.
It is also an object of the invention to provide an improved method and system for providing light of different polarization states to an LCD which programmably transmits selected polarization states for image display on a projection screen.
It is also an additional object of the invention to provide a novel method and system including a voltage adjusted LCD for controlled transmission of selected polarization states for reconstruction as an image on a projection screen.
It is yet a further object of the invention to provide a novel system and method for splitting different light polarization states of an image and using a compact mirror system to reassemble and display the image onto a projection screen.
It is an additional object of the invention to provide an improved system and method for manipulating polarized light using a polarization converting mirror plane that is optimally tilted with respect to a reflecting plane whose reflectance or transmissivity depends on polarization state and that is parallel to a viewing screen which can embody a Fresnel lens, to fit within the minimum possible volume and to output a single polarization state image for display on a projection screen.
It is another object of the invention to provide an improved method and system for controlling differently polarized light beams using a highly compact planar mirror system in conjunction with polarization converter elements to output an image onto a projection screen.
It is another object of the invention to provide an improved system and method for controlling differently polarized light beams using a highly-compact planar mirror system in conjunction with polarization splitting and converting elements to output an image onto a projection screen.
It is still another object of the invention to provide an improved system and method using polarization splitter films to separate different polarization states of an image for projection onto a screen.
It is another object of the invention to provide an improved optical system and method for display of an image on a projection screen, including a highly compact lens and/or reflector system having a spatial light modulator insensitive to polarization state of light.
It is also a further object of this invention to improve the contrast of a projection screen system by placing the elements of a bracketing lens pair between the output of the illumination source and the entrance pupil of the projection lens.
It is still a further object of the invention to improve the throughput efficiency of a projection system by placing the positive and negative lens elements of an approximately telescopic lens pair between the illumination source output and the aperture of an SLM.
It is yet a further object of this invention to correct for aberrations in isolated sections of a projection screen illumination system by including that section within the elements of a bracketing or other specified optical lens pair, using either conventional lens elements or lens elements with one or more of their surface functions modified with aspherizing terms.
It is yet a further object of the invention to provide a novel optical display system and method for generating tiled image portions which can be assembled to produce an enlarged projection screen display of a full composite image.
It is yet an additional object of the invention to provide a novel system and method for display of an image on a projection screen using polarized light and correcting for an image hole arising from a hole in the light input structure of the system.
It is yet a further object of the invention to provide an improved system and method for manipulating polarized light for display of an image on a projection screen using conicoidal elements coupled with a beam compressor element to eliminate an image hole arising from a physical hole in one of the conicoidal elements.
It is still another object of the invention to provide improved methods of expanding and compressing beams of light using physically separated prismatic Fresnel-type layers or conic forms of refractive material.
It is also an additional object of the invention to provide a novel system and method for manipulating polarized light using at least one ogived or tilted conicoidal element to eliminate a hole in a display image arising from a physical hole in one of the conicoidal elements.
It is another object of the invention to provide an improved system and method for efficiently transforming the cross-sectional shape of an optical system""s light beam, from circular to rectangular, using reciprocating conicoidal mirrors and a beam expander device to recycle light from the periphery of the circular input beam, to the central portion of the rectangular output beam, with good cross-sectional beam uniformity and without any light passing through or near the light source or arc.
It is still another object of the invention to provide an improved system and method for efficiently transforming the cross-sectional shape of an optical system""s light beam, from circular to rectangular, using an adiabatically varying lightpipe cross-sectional area combined with a total internally reflecting non-imaging optic angle transforming element.
It is another object of the invention to provide a compact means for converting an unpolarized beam of rectangular cross-section into a single rectangular beam divided into adjacent regions of uncontaminated orthogonal polarizations, using combinations of prisms and polarization-selective coatings.
It is still another object of the invention to provide a compact means for converting an unpolarized input beam into a polarized output beam free of contaminating polarization states, using a conicoidal polarization converting reflector with physical inlet hole combined with reciprocating composite lens elements and a flat or weakly curved plane of polarization selective material.
It is an additional object of the invention to provide an improved system and method for manipulating unpolarized light by means of reciprocating conicoidal mirrors, beam expanders, positive and negative lens elements and polarization-selective reflecting materials, so as to output a single beam of light having rectangular cross-section and two adjacent regions of uncontaminated orthogonal polarizations.
It is a further object of the invention to provide an improved method for increasing the throughput efficiency function of an optical system by means of a reverse raytrace process that interatively launches rays from the entrance pupil of a projection lens, back through designated launch points on an SLM and through the system""s interatively aspherized lens and reflector surfaces, to a target area corresponding to the system""s light source.
It is still a further object of the invention to provide an improved method for increasing the throughput efficiency function of an optical system by means of a reverse raytrace process that further includes weighting factors for the actual spatial and angular properties of the system""s light source.
It is yet a further object of the invention to provide an improved method for increasing the throughput efficiency function of an optical system by means of a reverse raytrace process that further includes weighting factors for intrinsic brightness non-uniformities that are observed on the system""s projection screen or on the system""s SLM (image) plane.
It is also an object of the invention to provide an improved system and method for producing and manipulating orthogonally polarized light of selected colors using an LCD color-splitting prism cube, polarization-selective coatings and prism elements, so as to output either one tri-color beam composed of two uncontaminated orthogonal polarization states, or two uncontaminated orthogonally polarized tri-color beams, each having passed through separate portions of each color""s LCD image.
It is a further object of the invention to provide a novel optical system using two cross-firing LCD color-splitting prism cubes and intervening polarization-selective coupling elements, for the purpose of outputting a single beam whose orthogonal polarization states correspond to separate color images, which then are processed for one of three-dimensional viewing, increased image resolution or image comparison.
It is also a further object of the invention to provide an improved system and method having a folded mirror, asymmetrical arrangement with a polarization splitting (also referred equivalently as polarization selective reflecting) mirror enabling substantial reduction of depth of the projection system.
Other objects and advantages of the invention will be apparent from the detailed description and drawings described hereinbelow.